1. Field of the Invention
The present invention relates to a printhead cartridge for a printer. In particular, the present invention discloses a printhead cartridge with asymmetrical contacts that enables a size reduction in a corresponding flexible circuit board (FCB) within the printer.
2. Description of the Prior Art
Please refer to FIG. 1. FIG. 1 is a perspective view of a prior art printhead cartridge 10. The prior art printhead cartridge 10 comprises an inkwell 12 and a tape automated bonding (TAB) structure 14. The TAB 14 is mounted on the inkwell 12, wrapping around from a front surface 15 to a bottom surface 19. The TAB 14 comprises a plurality of contacts 16, each with a corresponding trace 17 that electrically connects to a printhead 18. The printhead 18 is mounted on the TAB 14, and is disposed on the bottom surface 19 of the inkwell 12. The printhead cartridge 10 exhibits great symmetry along a cross-section Axe2x80x94A. If the printhead cartridge 10 were to be split down the middle along the line Axe2x80x94A, each half of the printhead cartridge 10 would have approximately the same number of contacts 16 (depending upon the parity of the number of contacts 16), and half of the printhead 18. The inkwell 12 is used to hold ink (not shown), and to provide this ink to the printhead 18. The printhead 18 performs a printing operation by jetting ink according to signals received from the contacts 16.
Please refer to FIG. 2 with reference to FIG. 1. FIG. 2 is a perspective view of a prior art printer 20. The printhead cartridge 10 is adapted for use in the printer 20. The printer 20 has a carriage 22 that holds two of the printhead cartridges 10, carrying the printhead cartridges 10 back and forth along a print track 24. The two printhead cartridges 10 are held as closely together as possible within the carriage 22. With each pass along the track 24, the printhead cartridges 10 form a print swath on a sheet of paper 21. Generally speaking, one of the printhead cartridges 10 performs a black-and-white printing operation, whereas the other printhead cartridge 10 performs a color printing operation using cyan, magenta and yellow inks. Together, the two printhead cartridges 10 are able to perform a full-color printing process upon the sheet of paper 21.
Please refer to FIG. 3 with reference to FIGS. 1 and 2. FIG. 3 is a schematic diagram of a flexible circuit board (FCB) 30 within the printer 20. The FCB 30 is disposed within the carriage 22 and is used to establish electrical communications with the printhead cartridges 10. The FCB 30 has a plurality of dimples 36, each of which establishes an electrical connection with one of the corresponding contacts 16 of the printhead cartridges 10. In this manner, the printer 20 is able to control the printhead 18 of each printhead cartridge 10.
The cost associated with the FCB 30 is related to the overall surface area of the FCB 30. By reducing the size of the FCB 30, it should be possible to reduce the total cost of the printer 10.
It is therefore a primary objective of this invention to provide a printhead cartridge with an asymmetric distribution of contacts to reduce a size of a corresponding contact surface within a printer.
Briefly summarized, the preferred embodiment of the present invention discloses a printhead cartridge that mounts within a carriage of a printer. The carriage moves along a first direction within the printer. The printhead cartridge includes an inkwell for storing ink, which has a front surface and a bottom surface, a printhead mounted on the bottom surface, and a plurality of contacts for receiving signals from the printer and to provide the signals to the printhead. A centerline of the front surface, running perpendicular to the first direction, evenly defines first and second sides of the front surface. The contacts are disposed on the front surface, and a distribution of the contacts on the first side exceeds a corresponding distribution of the contacts on the second side.
It is an advantage of the present invention that by providing an asymmetric distribution of the contacts of the front surface of a printhead cartridge, two such mirrored cartridges will form a combined density of contacts that is higher towards their combined center position. The traces on a contact surface within the carriage of the printer can be made to run between two columns of dimples. The size of the corresponding contact surface can be reduced as a result of this, which leads to a total lower cost of the printer.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings.